The joys of apartment living! Who does that?

Last year I had a girl with a little yappy dog move in next door to me & I had to complain because the damn dog barked non-stop when she wasn't home...like I listened to it bark while I was home sick one day for 10 straight hours. Well recently I realized she didn't live there anymore (shows how aware I am) and then last weekend I noticed a new door mat so I assumed that someone must have moved in.  I haven't yet seen my new neighbor but I think it's a guy just because I could hear a deeper voice echoing when I was in the bathroom yesterday but it could have been from the apartment below me, it's hard to tell sometimes.  Anyway, around 10:30 the neighbor was making so much damn noise it was ridiculous, a lot of banging on the floors to the point that my chair was shaking & I thought it sounded like someone doing gymnastics & jumping off of the couch...like I used to when I was a little kid.  After about 10 minutes it stopped & I went to bed at about 11:30 & curled up with my book when I heard the creek of the main door outside my apartment door & then the slamming of the door downstairs as someone left.  Two minutes later I heard the main door slam shut & then the door outside mine creek as the person came in & then two minutes later repeat the same cycle.  At about 11:50 I heard a car honk & then the neighbor leave yet again & this time I got up & looked out the window & it appeared to be a dude about 16 years old or at least that's what it looked like to me.  This confused me because I live in a 1 bedroom building & a 16 year old certainly isn't well off enough to be living alone nor would my company rent to someone under the age of 18.  

Ok, let's fast forward to about 12:15 when a car pulled in blasting hip hop which I have nothing against but there is no reason for anyone's music in their car to be that loud ever let alone at midnight...the music was so loud I couldn't hear the TV I had on in my room & I could hear each lyric crystal clear.  I could hear two people yelling over the music outside as well which made no sense whatsoever...why not turn down the music to talk rather than yelling?  Well, as I was about to call the police the music stopped so I shut off my light to go to sleep & then someone buzzed my fucking buzzer...at 12:30!  Do you have any clue how high I jumped?  It scared the living shit out of me & then I heard my neighbor buzz the person in & I think it was the person who left like 5 times in 10 minutes who I believe is also the person who was talking over the music.  I'm assuming this must also be the douche who was buzzing me repeatedly on Monday afternoon trying to get in the building but I don't buzz in people I didn't invite over.  

If I have to put up with this shit again I am calling the police as well as the apartment manager because this is ridiculous but I'm really curious to also see who is living in there!  If it's more than one person & not a couple I'd like to know where in the hell the 2nd person is sleeping, I mean, my apartment is a good size but it's not big enough for 2 people, especially 2 people that aren't a couple!